Objective:To explore the effects of cerebrospinal fluid contained Sijunzi Decoction on function of colon mucosa lymphocytes of ulcerative colitis in vitro. Methods: Prepared the rat cerebrospinal fluid contained Sijunzi Decoction or Mesalamine. Collected colon mucosa of the 12 healthy ( as normal group ) and 18 ulcerative colitis, then isolated and obtained lymphocytes from these samples. The lymphocytes were divided into pathological group, IL-12 group, cerebrospinal fluid group cerebrospinal fluid contained Sijunzi Decoction group, cerebrospinal fluid contained Mesalamine group. After exposing to various treatment,the proliferative capacity was measured by CCK-8,the cell cycle and the ratio of CD4+T was analyzed by flow cytometry (FCM), the content of IL-1, IL-6, TNF-α was detected by ELISA. The expression of IL-2 were detected by Western blot analysis. Results:Compared the cerebrospinal fluid contained Sijunzi Decoction group with the IL-12 group or cerebrospinal fluid group,the proliferative capacity and the percentage of CD4+T was decreased, the cells significantly arrested at G0/G1 phase, the secretory capability of IL-1, IL-6, TNF-α were obviously reduced; the expression of IL-2 was also significantly down-regulated. Conclusion:The cerebrospinal fluid contained Sijunzi Decoction could decrease the function of colon mucosa lymphocytes of ulcerative colitis,the mechanism involved in may be Sijunzi Decoction regulating the secretory capability of IL-1,IL-6 and TNF-α.